Safety valve



June 12, 192s. 1,673,470

A. W.VPUFFER SAFETY VALVE Filed Deo. 18. 1922 RIM K .f 16k 1p PatentedJune 12, 1928.

PATE-:NT orf-gica ALVIN W. BUFFER, or Mun-Fono,.,MAssAcHUsnrrs,AssIGNon. Tourneur: MAN-URAC- 'rUnING COMPANY;onwrncrrnsrnn,MASSACHUSETTS, A conronh'frron' or MAINE;-

serETY vaLvn.

Arppliqetin @15d Dee-enter; 18, 1.322. semaine. leinem.

Thisinvention relatestma Safety -valve 01' use in connection .withvessels containing luid under pressure.

` One object of the invention is toprovide a novel and efficientconstruction ofsatety valve which maybe nsedto advantage in connectionwith andform'a part of the regularequipment of unfired pressure vessels,such kas compressedair tanks .and the like, and which furthermore is ofsuch construction asto prevent tamperingwitlhy the4 valve controllingoradjusting mechanism, ,theren by preventing alteration .of thepressurefor which thevalve isset to operate after the valve has beeninstalled in the tank or vessel.`

Another object of the invention Lis to providea construction of'safetyvalve .which eliminates or at least reduces toa minimum, inthe eventthat the. valve has becomede fective or worn so as to leak, thepossibility of plugging l the safety valve vand using. the same in thetank oryvessel 4asa merel plug when ,its external. appearance is suchas/to give no warning to an inspector that it vis in fact defective .orinoperative.

Provision "is also `madefor likewise eliminating or kat least'reducingto a minimum ther possibility of plugging' up ,the spud or opening inthe tank inwhich the valve is normally received;

These and other features ofthe invention will be hereinafter describedland vparticularly pointed out in the claims.

In the drawing illustrating the lpreferred form of .the invention,Fig.`1 represents in elevation an unfired pressure vessel ,such p as acompressed air tank provided with a safety valve embodying thisinvention; Fig. Q a vertical `section of the improved safety valve andvalve Spud; Fig. 3, a Vcross section on line 3-3, Fig. 2 viewed in thedirection of the arrows;` Fig. 4 a Cross ,Sec tion on line 4 4; Fig. 5,a plan and Fig. 6 an elevation of the seat member shown yin Fig. 2, andFig. 7 an underside view of the seat member. y

Referring to the drawing, 1,0v lrepresents a tank or vessel adapted tocontain lfluid under press-ure, such for example, as compressed air.rlhe tank or vessely 10 1s provided with the `improved safety valve,preferably made as shown and comprising a valve proper 12, a Seat member`13, which is preferably screwed into a spudlt `having base secured byrivetsLl and solder 17 or in other suitable mannen'to ythe body, of thetank l() in position so that the tllljeadedfhole the spud 141 isinksubstafntial kalignment with a hole 1S in the said tank.

` The valve 12 is preferably made as a diaphragm of rubber or othersuitable inaterial, and is ,normally held in engagement with the uppersurface `of the seat member 13, which constitutes the Yseat orsaidvalve, bythe compression in a coil sprin`g22, the lower `end of whichrests lagainst ayplate23 by which the pressure of the spring isdistributed evenly over the upper'surface `of the valve12`to therebyinsure a tight'ioint between thefvalve and its seat.

,'lhe plate is providedwith arelatively short upstanding stem 24embraced bythe lower end ot' thefspring 2 2.l The desired compression inthe spring 22 isradjustably secured bypan ladjusting screw 25, which isscrewed through ,a threaded hole'in'the top of a valve casing or housing26, and which bearsragainst aplate 27 positionedI uponthe top of thecoil spring 22`bya depending rod g 28 extended downf into thes ring.`QThe pressure at `which the valve 12 will open may therefore be adjusted`by means oi' the screw25. y

The fluid pressure from within they tank 10 lis transmitted to theunderside ofthe' valve 112 through the hole 18 inthe tank bodyandthrough a central passage 29 in a stem `30 of `theseat member`1?),.tl1ence through a `pluirality of branching passages 31 to anannular channel `252 in the seat for the valve l2. yWhen the valve 12istorced upwardly froniitslseat by they fluidpressure on its underslide,`the fluid passes from the annular channel 32 overthe interveningportion of the valve seat and into a 'central opening 33 and thencethrough a plurality of inclined discharge passages BiltseeL dottedlines` Fig. 2),`leading outwardly to andterminating at the upperportionvvofvanlopen invertedy groove orchannel 35 in the lower surface of theYseat member 13. ln order to prevent or, atleastwminirnize unauthorizedtampering with the; ,safety valveand themechanisinfor adjusting theypressure for which the valve is set, provision is made for locking theadjusting screw 25 to the valve casing 26 and l tor locking thevalvevcasing 26 to ythey seat member 13;"Y For this purpose, n afterthelcompression in the coil spring 22has been adjusted to setzv the valvefor `a predetermined pressure inthe tank, the adjusting screw 25 ispinned to the valve. casing 26 by a pin Uv/hen the val ve is madeasshown inFig. 2.

The threaded'hole in the valve casing in which the adjusting screw 25 isreceivedand the hole in the valve lcasing through which the pin 36 isdriven, are hoth then soldered to conceal the screw and pin. i

The valve casing 26 isy designedto receive the seat member 13, whichlatter is` provided with externalfscrew threadsf? to engage internalscrervl threads on the` inner surface of the casinggand the latter ismade deep enough tol permit its lower end 38 to he wiped under thetaperedfunder, surface B9 of tlievseat member 13 and'forin a means forlocking j both parts ytogether ,and practically eliminating the liabilitofy separation of theseparts with any oA the tools available tojtheusual persons employed where compressed air tanks and the likev arelocated.

This construction renders access 'to the coil spring`22 and theadjusting'screw 25 a difficult` matter and practically impossible fromthevievfpoint of the nianonthe job, so that after thesafety valve hasbeen assembledbv the manufacturer and adjusted for a predeterminedpressure, its operation injpractice at suchpressure is renderedpractieally, certain as, far asunauthorized tamperingis concerned. n' fWith the ordinary sels, in the eventthat the valve vbecomes `devalve,plug it up in any one of several ways, andL thereafter replace 1t 1noperative position in the tanks.l From its external lappearance there isnothing to indie-ate that the valve is not acting ina normalinanner, sothat oftentimes the inspector passing the tank sees the safety valve inplace and to all intents andpurposes `in an operative c'ondif tion, andtherefore in many instances safety valves pass inspection When in factthey Vare really defective'andinoperative. l

yThe present invention also has for its object to eliminate the chanceasfar as possible, of the valve being pluggedyby the man on the joh withthe tools ordinarily!available to him, so that once a leak develops, it

is necessary inforder to stop the leak, to re-` place the rsafety valveWith a nevv7 or operative safety valve. Then thereforel an inspectorseesoneof the present valves in place on a tank, he may be reasonably surethat it.v

is in operative condition ifihe does not detect leakage` fromexternalinspection. f

Accordingly the plugging `of the discharge passagesl is practically madeimpossible j by the channell or groove 35,"Which is of sufficientdepth'so that the walls thereof prevent construction of safety valveused 1n connectlonwith unfired ves-l the introduction intothe inclineddischarge passages 34 `of"straightv 'plugs of any'sort.

` This construction therefore prevents plug? kging of the safety .valveAfrom the discharge ,or outlet side of thevalve; f f n In addition tothis feature, provision 1s ing or hole 18 in the tank, if theopen'ing18/ should Ahe smaller than the hole in the spud.

Iffsuch an attcmptisimade vifith the illus,` trated construction, thepressure of the projecting endy 47 of the valve stem will engage thepenny or plate yor jdiskat one side of its center and cause the penny,etc." to" tip, thus permitting the fluid under pressure Within the tankto leak around 4and into' the space orchamber formed by the undercut,

portion 4,6 of the base of the yvalve Spud. This s ace bein in directcommunication with t ie 'centra inlet passage 29' through the valve,vstem' peri'nits the fluid to pass through the 'defective'` valve 'andescapethrough the discharge'passages' 34. y

In eorderpt'o prevent the plugging 'or sol-v deringu )of the lower end"of the inlet pasl" sage 29 from successfully plugging ,the en-y tiresafety valve, a radial port or hole" 48is provided in the lowery'externally threaded end portion of the valve stem, which port extendsfrom one ofthe threads inthe valve stem tothe central inlet passage 29asshown in Fig. 2. The Wall of thevalve Spud 4also provided with aplurality of axially arranged slots 49, which areextended vertically asuiliclent distance to enable the fluid pressure, in the event that thelower end of` the central inlet passage is plugged, to b vpass throughthe slots ,49, through the threads in thevalve spud and-thence throughthe afi ibi

radial port or hole 48 into `the central inlet passage 29, from whichvthe fluid will escape through the defective valve and issue from thedischarge passages 34, thus warning the inspector that the valve isdefective.

lVhen `the improved safetyy valve is installed in the pressure tank, itisdesirable that the openingr or hole 18 in the tank he madesquare. Thiswould operate as an ad ditional obstacle to the successful plugging ofthe hole by a coin or plate passed down l through the hole inthe Spud,nthose cases where the size of the `hole in the spud and the hole in`the tank were substantially the same. l i i In addition to eliminatingas far as ypossible the chance of the workman plugging the inlet oroutlet passages .off the valve,and then usingthe .vaaflve `as asolidplug, it is desirable that the spud 14 itself should be .of suchconstruction as to negativel the useofa plug having lan ordinary threadin the spud.

Accordinglythe Vthreads upon the interior of the spudand the threads 4onthe .lower` end ot the zstem 3() are `made special, "being other than 2astandard. pipe thread.

.In order to prevent an ordinary leather or other washer being used onthe threaded' portion ofthe stem .toltorm a tight joint n with the uppersurface ot' the Spud, thelatter is provided with a valve seat 50 belowits upper edge, With which cooperates a valve 51 on the valve stem 30.The portion or' the spud above vthe valvefseat 50 is provided with slots52 so as to prevent closure ot the spud by a Washer mounted on the valvestem 30 below the valve 51 thereon. In such case, the valve 51 on thevalve stem 30 Will be raised off of its seat 50, and a free passageaiforded from the tank through the threads ot' the valve stem andthrough the slots 52 intothe atmosphere.

In the normal operation of the safety valve, the valve 51 on the stem 30is seated on its seat 50 in the spud and a tight joint is obtainedWithin the Spud.

The` diaphragm valve 12 When made ot' non-metallic materia-l may beprotected against injury by a metal ring 53 interposed 'between thevalve casing 26 and the upper surface of the diaphragm valve.

One embodiment of the invention is herein shown, `but it is not desiredto limit the invention to the particular construction shown.

Claims: i

1. In a safety valve, in combination, a valve seat, a valve cooperatingtherewith, a spring for normally holding the valve upon its seat, avalve casing enclosing the valve, valve seat and spring, a screw foradjusting the said spring, and a pin Within said casing inaccessible forremoval from the ex terior of the casing and engaging said screw forlocking the screw tothe valve casing and thereby permanently locking thespring in its adjusted position.

Q. In a safety valve, in combination, a valve casing having an openingat one end thereof, a. seat member for said valve screwed into saidopening and normally closing the same, a valve Wit-hin the casingco-operatingl with said seat member, means Within the valve casing fordetermining the pressure at which the valve opens, said casing having aportion bent under the said seat member to lock it from being unscrewedfrom said casing. Y

3. In a safety valve, in combination, a valve casing, a valve Within thesaid casing, a seat member for said valve, a spud adapted to be securedupon a vfluid pressure tank, and means for securing a tight jointbetween the stem-and spudincludinga valve seat Within thel spudand belowthenotch therein,a1nd an auxiliary valvemember on the :said stemcooperating therewith. i

15. In a safety valve, in combinatiom a valve casing, a'fvalve `withinsai-d casing, a seatrmeinber-.for said Valve, a spring-Within saidcasingfor normally holding said valve to its seat, and means on said casingextended under` and engaged with said seat memberk for mechanicallylocking the said seat mem ber to sai-d casing. i

6. In a safety valve, in combination, a valve casing, a valve Withinsaid casing, a seat member for said valve having a head engaged Withsaid casing and a stem extended from said head outside of said casing,

a pressure inlet passage in said stem extended to the seat for saidvalve, an inclined pressure outlet port extended from said valve seat tothe underside of said head, and means i'or locking said seat member tosaid casing. i o

7 In a safety valve, in combination, a valve casing, a valve Within saidcasing, a seat member for said valve having a head engaged with saidcasing and a stem extended from said head outside of saidcasing, apressure inlet passage in said stem extended to the seat for said valve,an annular channel in the under side of said head, and an inclinedpressure outlet passage extended from near the botom of said channel tosaid valve seat.

8. In a safety valve, in combination, a`

valve casing, a valve Within said casing, a seat member for said valveconnected With said casing and havlng a stem extended outside ot saidcasing, a `valve on said stem, a

spud having a lvalve seat with which the `valve on saidstem co-operates,and means `for connecting said valve stem With said `with externalscrew-threads and having a pressure passage extended fromsaid threadedportion to said longitudinally extended pressure passage.

10. The combination With'a spu'd having a pressure outlet port in itsupper end, and provided on its inner surfacebelow said outlooletvportwith a Lvulve seat and with fseew# threads, :ofa rsafety valvehaving astem p`ro.

vided with a longitudinally extended ypres- Sure passageandwith.screw-threads to engage the serew threadsvof,soiclspud und. withavalveto engage theseatiwithin seid spudl1 x 11. The combinationwith aspudwhaving screw-threads ^on its inner 1surface` and :in axiallyextended port formed insai-d? screw` threads and extendedhut partiallythe length of the Spud, of a safetyfvalvehavingnistem provided with `a1'longitudinally extended 'pressure passage und withserew-threads ltoengagethe `screw threads of Said Spud and having *a port extendedffrom'l the 1 longitudinal 1pressure pusssuggey to the screw-threadsthereof to establish eommunicntion between l naine to thisspecification.l

yvalve and screw-threads offthesuid Spud,

und huvinglitszend cntmvny to form `a port l extended Ilaterally fromthe axiallyy extended pressureA port toL the outer surface of thevalvevr stern.` v j l nn y y :l y y ln testimony. whereof, :I dmvesignedmy

